The subject application relates generally to a header for use with agricultural harvesters. In particular, the subject application relates to an improved skid shoe for use with pull-type or self-propelled mower headers.
Mower headers have been used to cut plants including, but not limited to, hay, grasses, small grains and the like for many years. Such mower headers are often referred to as Disc Mower Conditioners (DMCs). A pull-type DMC is pulled by a tractor and can have a trailing tongue that pivots and is attached to the left side of the header trail frame or chassis (Side Pull DMC) or it can have a trailing tongue that pivots and attaches to the center of the header trail frame or chassis (Center Pivot DMC). Side pull DMC's can only pivot to the right of the tractor and center pivot DMC's can pivot to the left or right of the tractor. The cutting of the DMC, whether pull-type or self-propelled, is typically performed by a disc cutter bar. The cutterbar is made up of multiple discs arranged in side-by-side relationship with each disc having a plurality of cutting knives. The discs spin at a certain RPM sufficient to cut the crop. The knives and discs then feed the cut crop into a conditioner. At present, there are two types of conditioners: roll conditioners and flail conditioners. The rolls can be either rubber, urethane or steel. Which conditioner is used depends on the crop being cut. After being conditioned the crop is propelled out the back of the DMC and onto the ground. Adjustable shielding in the back of the DMC allows the operator to lay the cut crop in a swath such that it covers the ground like a carpet or mat or in a windrow whereby crop lays in a tall row. The manner in which crop is laid on the ground (mat or windrow) depends on whether the crop needs to be dried more and/or how it is to be picked up and packaged.
Whether pull-type or self-propelled, DMCs are normally equipped with stationary skid shoes under the cutting elements or a long pan that slides along the ground under the cutting elements. The skid shoes or pan serve as a wear surface to protect the expensive cutting elements from excessive wear. DMCs may also have the option to be equipped with vertically adjustable skid shoes provided along the cutterbar for setting the height of the cutting discs with respect to the ground surface. The vertical adjustability of the skid shoes is useful for several reasons. For example, the crop being cut may need to have a relatively higher or lower stubble height after being cut. In this instance, the adjustable skid shoes allow the cutterbar to be raised or lowered accordingly. They can also be appropriately adjusted if a farmer is harvesting a field populated with a lot of obstructions such as rocks. In this case, the cutterbar can be raised so that the knives do not strike and become damaged by the obstructions or rocks.
Skid shoes are rigid members, usually formed of rugged, wear resistant material including but not limited to metal or hardened plastic. During operation, the skid shoes slide over the ground and the weight of the header is borne in large measure by the skid shoes. A conventional skid shoe includes a fore end, an aft end and lateral sides extending between the fore and aft ends. The fore and aft ends are normally upwardly extending. The lateral sides are constructed with flat lateral edges which lend themselves to destructive soil contact as the header is turned, as further described below.
A considerable disadvantage of conventional adjustable skid shoes is that they tend to forcefully penetrate into the soil as the header is turned to the left or to the right. More particularly, as the header pivots or veers from a straight heading, it pushes the radially innermost lateral edges of the skid shoes sideways and downwardly in the direction of the turn thereby applying more force on the radially innermost lateral edges of the skid shoes. The result is that the flat lateral edges of the skid shoes tend to dig or plow into the soil. This forceful lateral soil penetration leaves divots, streaks and ruts and accelerates wear/damage of the skid shoes, and damage to the crop in the field.